Process for refining hydrocarbon oils



1940; G. A. LORENZ 2,224,636

PROQESS FOR REFINING HYDROCARBON OILS Filed Dec. 8, 1939 Phosphoric Acid Solufion q Dish'llofe Vapors N ifroqenous l9 Sludge lnvenror: Geo. gm

61; his Aflorneg:

Patented Dec. 10, 1940 UNITED STATES PROCESS FOR REFINING HYDROCARBON' OILS George A. Lorenz, Edwardsville, Il1., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application December 8, 1939, Serial No. 308,152

11 Claims.

This invention relates to a process for refining hydrocarbon oils in a heated condition and preferably in the vapor phase by contacting same with a chemically acting acid refining agent, and more particularly is concerned with the vapor phase refining of fuel distillates such as gasoline distillates at elevated temperatures with aqueous solutions of phosphoric acid.

The'use of phosphoric acid in the refining of hydrocarbon distillates is known. For example, hydrocarbon distillates either in the liquid or vapor phase may be conducted at temperatures between about 300 and 750 F. over or through a stationarybed of a contact reagent comprising phosphoric acids deposited on metallurgical coke.

In contact with the hydrocarbons, the catalystis gradually spent, and when it is finally exhausted the'treatment is interrupted. Residual phosphoric acid may be removedfrom the carrier by washing it with-water, acetone or other suitable solvent for phosphoric acid and may thus be recovered in part. The 'coke is then drenched with a strong solution of freshor recovered phosphoric acid and the resulting mass is dried. Thereafter the refining treatment may be resumed.

While the above method is capable of effectively refining hydrocarbons containing unstable compounds to yield distillates of satisfactory stability, it is somewhat cumbersome in the matter of regenerating the refining reagent, the cost of the regeneration of the catalyst constituting-a large part ofthe total .refiningcost.

It is the purpose of this invention to refine hydrocarbons preferably in the vapor phase with phosphoric acid in a manner so that. the expensiveregeneration of 'the catal-yst bed is obviated. Another purpose is tostabilize unstable hydrocarbons satisfactorily while a minimum amount of phosphoric acid is consumed, and .a minimum loss-of hydrocarbons .issustained; and it is a-further purpose to provide an economical refining method in which the octane numbers of the-ga-soline distillates .are regularly and materially increased.

I have found that unstable hydrocarbon dis tillates can be-refmed satisfactorily by contacting them ina suitable treating zone, while in a heated condition, with an aqueous solution of phosphoric acid in an amount which is just sufficient to effect the desired degree of refining and which iscompletely-consumed,.i. e., converted to sludge, in a once through operation, and to produce-twolayers only, a hydrocarbon layer and a sludge layer. The hydrocarbon .layermay-consist of one or. .two phases, .i. e.,.it may be gaseous liquid or both- If an excess of phosphoric acid is used, then three layers will separate, namely, a hydrocarbon layer which also may .be vapor or liquid or .both, a layer consisting-essentially of free phosphoric acid with. varying amounts of water, and a sludge layer. It is essentialfor my process that the maximum amount of phosphoric acid employed be less than that required to cause. the separation of a free phosphoric acid layer after prolonged standing, i. e.-, in the successful operation of. my process there will be no layer. of free phosphoric acid separated.

The reasons for the improved results of my invention are explained below and-seemto reside in theme of thevery small. amounts of acid. limited as set forth above. It is believed that during the contact ofthe reagent solution and hydrocarbons, several reactions take place almost,

simultaneously-as follows: Water. of solution begins to vaporize immediately, whereby the reagent. within the individual droplets or the film is-concentrated rapidly. Simultaneously the phosphonic acid begins toreactwith the most reac'tive' components in the hydrocarbonsthereby diluting itself with its own compounds of. reaction. has, the time .of contact progresses, the phosphoric acid is eventually completely converted to sludge. It will thus be seen that the reagentsolution is in a continuous state of change, its concentration asWell as composition changing rapidly during the contact period. Moreover, the aciditself is at all times in a more or .less diluted condition, capable of converting to sludge and high boiling polymers the most reactive hydrocarbons only, e. 'g., diolefines, thereby effectively, stabilizing the hydrocarbon mixtureat-a minimum loss of valuable hydrocarbons. It. has been foundthat in the absence of gum inhibitor poisons such as polyrsulfides, or of gum promoters, the stability of a cracked. distillate as expressedin terms of .gum inhibitor susceptibility. is an approximate functionof its content of diolefines having conjugated double bonds in the distillate. In my treatment, polymerization losses areabout proportional to the amount of diolefines having conjugated double bonds and are of a magnitude to indicate thatthey are due primarily. to the polymerization of those diolefines only. Mono-olefines which are highly desirable components of gasolines and similar fuels, are little affected by my treatment. Hence treating losses caused by my treatment are about equal to the theoretical minimum which is compatible with. satisfactory stabilization. If. however an amount of reagent were used greater than that which can be converted to sludge, concentrated free phosphoric acid would be in contact Withthe vapor towardthe end of the reaction, with the result that substantial amounts-0f desirable hydrocarbons,- e. g.,.mono-olefines, would be polymer i-zed. I

Treating with an amount of phosphoric acid to avoid formation of a layer of free unconsumed acid has the additional advantage of obviating recirculating equipment for the unconsumed acid. This materially reduces the cost of the installation as well as of the operation.

The sludge formed as the result of the contact between the small amount of the phosphoric acid and the hydrocarbons is substantially free from water, has the appearance of a homogeneous mass, but actually contains substantial amounts of free or very loosely bound phosphoric acid, which is insufficient in amount however to form a separate phase. This sludge may be semi-solid or liquid under the conditions of the treatment. It deposits on the packing, and if sufficiently liquid, runs down to the bottom of the treating zone, from which it can be withdrawn. If it is semi-solid, it may plug the packing and force a shutdown of the treating operation. Obviously, for continuous uninterrupted operation the sludge should be sufficiently liquid so that clogging will not occur. I have found that formation of a liquid, though viscous sludge, is favored if nitrogen bases are removed from the distillates prior to subjecting them to my treatment. This may be accomplished by washing the distillates at about normal room temperature with aqueous solutions of sulfuric or other suitable acids which are sufficiently diluted, so that they will not substantially react with unsaturated hydrocarbons under the conditions or the washing; or by treating them in the vapor phase at temperatures between about 150 to 400 F. with dilute solutions of sulfuric, sulfonic or other suitable sulfur acids, preferably in ,amounts just sufficient to convert the nitrogen 'bases to their respective salts, but insuiiicient materially to react with unsaturated hydrocarbons in the manner described in the co-pending applications by Edmond R. P. E. Retailliau, Serial No. 208,697, filed May 18, 1938, and Serial No. 208,698, filed May 18, 1938. Removal of the nitrogen bases has the additional obvious advantage of materially reducing the consumption of the rather expensive phosphoric acid.

Besides nitrogen bases, mercaptans and other acidic compounds may, if desired, be removed by asuitable pretreatment such as washing with aqueous caustic alkali. However, acidic impurities do notnormally materially influence the effectiveness of my treatment; except that certain acidic .compounds, such as alkyl phenols which are powerful natural gum inhibitors, when allowed to stay in the distillate materially improve its stability after treatment.

After passing through the treating zone, refined hydrocarbon vapors and sludge are separately withdrawn and vapors are condensed.

' The resulting condensate is normally neutral and may be sweetened by any conventional sweeteningprocess. Vapor phase treatmentis preferred, although liquid phase treatment maybe used, particularly when treating relatively high boiling oils.

Oils susceptible to my treatment are in particular cracked gasolin distillates, although the process is applicable as well to special aromatic solvents, cracked tractor fuels having boiling ranges from about 200 F. up to about 575 F., distillate fuel oils such as the No. 1 to No. 3 fuel oils by the A. S. T. M. specifications D 396-34 T, which oils may boil between about 300 to 700 etc. A common difliculty of burners designed to operate on distilled fuel oils is the clogging of the screen through which the fuel must pass before combustion. This difficulty is largely overcome when treating the distillate fuel oils by my process. Moreover, as the result of the treatment, carbon forming bodies which have a tendency to cause soot are at least partially eliminated.

To provide an effective contact between the solution of phosphoric acid and the hydrocarbons, the former is effectively dispersed within the latter as by spraying, spreading over a large contact surface such as that of a packing, or other suitable means. The volume ratio of the phosphoric acid solution to hydrocarbon vapors being very small, treatment by passing vapors through a liquid pool of the solution is impractical, if not impossible.

Counter or concurrent treatment may be used. As a general rule, better results are obtained with concurrent treatment when treating a distillate substantially free from nitrogen bases; but when treating a distillate having a relatively high nitrogen base content countercurrent treatment usually'is more efficient.

The treating zone may conveniently consist of a vertical tower or column containing an inert relatively coarse packing, preferably metallurgical coke, which has a satisfactory mechanical strength and is known to be fully resistant to phosphoric acid as well as to the sludges formed in the treatment containing spent phosphoric and/or organic compounds thereof. However, other packing materials such as calcined phosphoric acid-silica, pumice, clay, charcoal, brick, tile, etc., may be used, if desired, at least temporarily, though many of these materials other than coke tend to crumble upon prolonged exposure to phosphoric acid.

As previously mentioned, the sludge is free from water and though apparently homogeneous when emerging from the treating zone is acid reacting and contains substantial amounts of free or very loosely bound phosphoric acid which amounts however are insufficient to form a separate phase. It is corrosive to many metals in contrast to the sludges formed by similar treatment with sulfur acids described in the hereinbefore mentioned Retailliau applications.

If the treating distillate is substantially free from nitrogen bases, at least a portion, i. e., usually about 90%,, of the phosphoric acid consumed in the treatment may be recovered from the sludge in the most simple manner, by first separating it from entrained hydrocarbon oil, washing it with a light hydrocarbon oil such as naphtha and then hydrolizing it at an elevated temperature preferably not below about 200 F., as by steaming or heating it with liquid water, if desired, under superatmospheric pressure sufficient materially to raise the treating temperature to above the normal boiling point of water. At substantially atmospheric pressure, a time of about 1 to 8 hours and more often 2 to 4 hours for hydrolysis and liberation of readily hydrolyzable phosphoric acid is usually sufiicient.

After completed hydrolysis an amount of water should preferably be present to result in a phosphoric acid solution of about 5 to 80% concentration. Such a solution will easily separate from the organic residue. The hydrolyzed mixture is allowed to settle, preferably while hot, whereby a lower aqueous solution of phosphoric acid is formed, which may be used in my refining process without further purification, concentration or other treatment; an upper hydrocarbon layer comprises polymers, some of which have the properties of useful resins.

Frequently however the amounts of phosphoric which I use are so small that the installation .and operation of a hydrolyzing and recovery system are not warranted. Moreoverthe phosphoric acids so recovered may contain considerable amounts of nitrogen bases, in which case these recovered acids are advantageously used to remove nitrogen bases from raw distillates and the resulting salts are then discarded.

The distillates resulting from my treatment are improved in regard to their color, color stability, gum, stability, susceptibility toward gum inhibitors, as is usual in chemical refining processes. Moreover, I have observed a constant increase in the octane numbers of gasolines treated by my process, the increase in the case of cracked gasoline being normally of the order of to 3 octane numbers and occasionally higher.

The most essential factors in my treatment are amounts of reagent, temperature and time of the reaction. Concentration of the aqueous phosphoric acid solution is of influence only in so far as it affects the ease with which the solution can be distributed throughout the vapors. Aqueous phosphoric acid solutions of high concentration are very viscous. and because of this the small amounts of the solutions required, there is danger of uneven distribution and consequent uneven treatment of the hydrocarbons if the solution is too concentrated. Therefore, it is in general desirable to use concentrations of about 30% or less. although I have successfully injected s0lutions having concentrations as high as and On the other hand, at relatively high treating temperatures I have used with equal success solutions having concentrations as low as .5%, and even lower concentrations may be employed if desired.

Amounts of reagents suitable for my treatment are normally between about A and 1 lb. and preferably less than about 4 lb. of reagent calculated as H3PO4 per barrel of distillate. In the treatment of full range Dubbscracked gasolines on plant scale /8 to ,5 lb. per barrel has proven very satisfactory. Tominimize consumption of reagent, the minimum amount which gives a satisfactory treating result and which is comnletely consumed in a single pass, as previously described, is obviously the most desirable. This minimum varies considerably with the type of distillate under treatment.

Suitable contact temperatures are in general of the order of about to 750 F., temperatures between about 350 to 500 F. normally being ontimum. Superatrnospheric pressures be employed if desired, and it is immaterial. from the point of view of refining efficiency whether a'portion of the distillate is in the liquid phase, although difficulties arise in the separation of the liquid portion from the sludge and from uneven treatment of the vapors and liquid portions. The effect of superatmospheric pressures is ma nly that of lengthening the time of contact in the treating zone for a given throughput. On the other hand, when treating relatively high boiling distillates. it may be advantageous to maintain a considerable vacuum in the treating zone to enable substantially complete vaporization and to prevent condensation of the distillate the most desirable treating temperatures if va or phase treatment is desired.

The time of contact may be varied between the limits of about 1 to 300 seconds-and preferably 3 to 90 seconds, and may if desired be extended beyond these limits. In general, at relatively low temperatures longer times of contact are permissible and required than at higher temperatures under otherwise equal conditions. Reaction times of less than about 3 seconds are normally insuflicient. With increasing time of contact above about 3 seconds, the stability of the hydrocarbon oil increases while treating losses may rise but little. On the other hand, if the contact is extended beyond a certain time which depends largely upon the temperature as well as on the properties of the treating distillate, stability is not further improved materially, and certain disadvantages make themselves felt such as increased losses and the extremely large size of the reaction vessel which is required for a given throughput.

As has been explained before, a considerable portion of the refining effect is due to the prolonged contact of the hydrocarbon vapors with the sludge. Therefore, it seems necessary that treatment be begun in a reaction zone in which the packing has been covered with sludge prior to passage of hydrocarbon vapors therethrough. This, however, is not usually practical and I have found it to be preferable instead to proceed as follows: First the packing is superficially wetted or thoroughly drenched with a phosphoric acid solution. Then the treatment of the hydrocarbon vapors is started. In the beginning of this treatment, I may not or may inject phosphoric acid solution into the vapors in accordance with my invention. For instance, it is often practical and economical to delay the injection until at least a major portion of the phosphoric acid on the packing is substantially exhausted, i. e., is converted to sludge. soon as the refined distillate begins to show signs of insufiicient treatment. In this manner I may combine the hereinbefore mentioned process of treating with phosphoric acid deposited on metallurgical coke with my own, whereby advantage is taken of both types of treatments, i. e., a thorough refining eifect is obtained from the start coupled with a practically unlimited continuous operation. Thus I have run the process continuously for many months and have not yet found it necessary to discontinue it in order to restore the packing.

Instead of carrying out the treatment in a single treating zone, I may employ several zones.

This may have the advantage of giving the process greater flexibility. I may maintain substantially the same conditions in the several zones, or operate them under different conditions or I may employ difierent refining reagents in diiferent zones. For instance, I may use sulfuric or sulfonic acids in the first zone and phosphoric acid in the following.

My process will be more fully understood from the attached drawing which represents a simplified illustrative flow diagram of one possible form of my process.

Distillate vapors from asource not shown enter treater I through line 2. To prevent condensation in the treater I steam may simultaneously be admitted through line 3. A dilute aoueous solution of a sulfur acid is injected into the top of treat-er l through line l, preferably in an amount just sumcient to convert nitrogen bases contained in the distillate to their salts. The vapors pass upwardly through a packing situated in the treater and the acids pass downwardly, nitrogenous sludge being withdrawn through Injection, however, should begin as to the vapors entering the treater'8. Into treater '8 is admitted through line San aqueous solution of phosphoric acid of convenient concentration, in an amount which in contact with the Vapors in the trea'ter 8 is completely converted to sludge, as has been explained above. The treater contains a suitable packing which is resistant to the sludge. The vapors and the acid or sludge respectively flow through treater 8 in a downward direction over the packing. Treated vapors pass through condenser ID in line H and the resulting condensate is accumulated in tank l2. Water separates out and may be withdrawn through line l3.

Sludge formed in treater 8 is withdrawn through line l5 and is mixed with water from line H. The mixture is conveyed by pump IS in line IE to the pressure hydrolyzer l! which is equipped with heating means such as a steam coil l8. Sludge is hydrolyzed. Dilute phosphoric acid solution settles out and the solution is returned to the top of treater 8 through line l9, or may be recycled back through lines l9 and 22 to treater l where it is utilized to remove nitrogen bases. Organic residue from the hydrolysis, i. e., hydrocarbon polymer is withdrawn from the hydrolyzer I! through line 20.

The following examples further serve to illustrate my process:

Example I A cracked unstable gasoline, substantially free from alkyl phenols and nitrogen bases, having an octane number of 67 was contacted concurrently in the vapor phase with a 10% aqueous solution of phosphoric acid in an amount corresponding to .083 lb. H3PO4 per barrel of gasoline at temperatures ranging from 300 to 600 F. The time of contact varied from 10 to 50 seconds. It was found that between about 350 to 500 F. the greatest overall improvement in gum stability, inhibitor susceptibility and octane number took place while polymerization and sludge loss remained low. For instance, at 500 F. and 13 seconds contact time the sludge and polymerization losses were 1.5%, the induction period without inhibitor was 4% hours, copper dish gum was 10, and octane number 70.

Example II A cracked unstable Mexican gasoline was washed with dilute aqueous solutions of caustic soda and sulfuric acid. The washed gasoline was then treated at 400 F. and at 500 F. concurrently in the vapor phase with Tg lb. phosphoric acid per barrel of gasoline in the form of a 10% solution with the following results:

Gum inhibitor susceptibility is defined as minutes increase in induction period upon addition of 1 mg. gum inhibitor per ml. gasolines.

The above gasoline treated with 1 lb. sulfuric acid per barrel in a conventional manner at room temperaturehas gum inhibitor susceptibility for the same inhibitor of the order'of 80.

Example III The washed gasoline of Example II was treated in two stages with twice lb. phosphoric acid per barrel of gasoline in the form of 10% aqueous solutions, using concurrent flow in both Induction period after sweetening with AgNOs, hours 7 Induction period after sweetening with AgNO3, after adding .001% by wt. UOP #2 inhibitor, hours 12% Gum inhibitor susceptibility 460 Example IV A cracked gasoline distillate, substantially freed from nitrogen bases and acidic components by washing same'with dilute aqueous solutions of sulfuric acid and caustic soda at room temperature, was treated in the vapor phase at 400 F. with aqueous solutions of phosphoric acid having difierentconcentrations, in amounts equal to lb./barrel H3PO4. Care was taken to insure even distribution of the solutions regardless of concentration, the vapors and phosphoric acid passing concurrently through a tower filled with coke. The time of contact was 10 seconds. While the concentration of the solution was varied between the limits of 10 to 85%, the qual ity of the treated gasoline remained approximately the same throughout. Its properties were as follows:

#2 inhibitor, hours 3% Inhibitor susceptibility Copper dish gu 10 This case is a continuation in part of my copending U. S. application Serial No. 214,885, filed June 21, 1938.

I claim as my invention:

1. In the process of refining a hydrocarbon oil containing chemically unstable components by treating same in a heated condition with a reagent which consists of an aqueous solution of phosphoric acid, the improvement comprising injecting into said heated hydrocarbon oil said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform Sludge in a single pass and to'produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insufficient free acid to form upon standing a free acid layer, conducting said hydrocarbon oils and phosphoric acid solution in intimate contact through a reaction zone at a temperature between to 750 F., maintaining said contact for a time suflicient to vaporize water of solution and to react at least a portion of said unstable components with the phosphoric acid thereby changing the concentration of said solution while producing a sludge, and separating the hydrocarbons from the sludge.

2. The process of claim 1 in which the hydroiii carbon oil and aqueous solutions are conducted through the reaction zone in concurrent flow.

3. The process of claim 1 in which the temperature in the reaction zone is between 350 and 500 F.

4. The process of claim 1 in which the concentration of the phosphoric acid solution fed to the reaction zone is between .5 and 30%.

5. In the process of refining hydrocarbon oil vapors containing chemically unstable components by treating same in a heated condition with a reagent which consists of an aqueous solution of phosphoric acid, the improvement comprising injecting into said heated vapors said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform sludge in a single pass and to produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insuflicient free acid to form upon standing a free acid layer, conducting said vapors and phosphoric acid solution in intimate contact through a reaction zone at an elevated temperature below 750 F. to prevent substantial condensation of the vapors, maintaining said contact for a time sufiicient to vaporize water of solution and to react at least a portion of said unstable components with the phosphoric acid thereby changing the concentration of said solution while producing a sludge, and separating the vapors from the sludge.

6. In the process of refining hydrocarbon oil vapors containing chemically unstable components by treating same in a heated condition with a reagent which consists of an aqueous solution of phosphoric acid, the improvement comprising injecting into said heated vapors said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform sludge in a single pass and to produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insufiicient free acid to form upon standing a free acid layer, conducting said vapors and phosphoric acid solution in intimate contact through a reaction zone at an elevated temperature below 750 F. to prevent condensation of the vapors, maintaining said contact for a time sufiicient to vaporize water of solution and to react at least a portion of said unstable components with the phosphoric acid, thereby changing the concentration of said solution while producing a sludge, and then extending the contact of the unreacted vapors and the sludge sufliciently to convert remaining unstable components to more stable products, and separating the vapors from the sludge.

7. The process of claim 6 in which the amount of phosphoric acid is between and 1 lb'. per barrel of distillate.

8. The process of claim 6 in which the time of contact is from 3 to 90 seconds.

9. In the continuous process of refining hydrocarbon distillate containing chemically unstable components by treating same in a heated vaporous condition with a reagent which consists of an aqueous solution of phosphoric acid, the improvement comprising injecting into said heated distillate vapors which are substantially free from nitrogen bases said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform sludge in a single pass and to produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insuflicient free acid to form upon standing a free acid layer, conducting said vapors and phosphoric acid solution concurrently in intimate contact through a reaction zone at a temperature between 150 to 750 F., maintaining said contact for a time sufficient to vaporize water of solution and to react at least a portion of said unstable components with the phosphoric acid, thereby changing the concentration of said solution while producing a liquid sludge, and separately withdrawing said sludge and vapors from the reaction zone.

10. In the continuous process of refining hydrocarbon distillate containing chemically unstable components by treating same in a heated vaporous condition with a reagent which consists of an aqueous solution ofphosphoric acid, the improvement comprising injecting into said heated distillate vapors which are substantially free from nitrogen bases said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform sludge in a single pass and to produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insufficient free acid to form upon standinga free acid layer, conducting said vapors and sludge concurrently in intimate contact through a reaction zone at a temperature between 150 and 750 F., maintaining said contact for a time sufficient to vaporize water of solution and to react all of said phosphoric acid with at least a portion of said unstable components, and to produce a liquid sludge substantially free from a separate phase of free phosphoric acid, and separately withdrawing said sludge and vapors from the reaction zone.

11. In the continuous process of refining hydrocarbon distillate containing chemically unstable components by treating same in a heated vaporous condition with a reagent which consists of an aqueous solution of phosphoric acid, the improvement comprising injecting into said heated distillate vapors which are substantially free from nitrogen bases said aqueous solution of phosphoric acid in an amount which under the conditions of the treatment is completely converted to a uniform sludge in a single pass and to produce two layers only, a hydrocarbon layer and a sludge layer, said sludge layer containing insuficient free acid to form upon standing a free acid layer, conducting said vapors and phosphoric acid solution concurrently in intimate contact through a reaction zone at a temperature between 150 and 750 F., maintaining said contact for a time sufiicient to vaporize water of solution and to react at least a portion of said'unstable components with the phosphoric acid, thereby changing the concentration of said solution while producing a liquid sludge, separately withdrawing said sludge and vapors from the reaction zone, subjecting said sludge to hydrolysis with water at an elevated temperature not substantially below the normal boiling point of water under conditions to produce two layers, one comprising a dilute aqueous solution of phosphoric acid and the other a hydrocarbon polymer, separating the layers and without further treating the phosphoric acid layer returning same to the reaction zone.

GEORGE A. LORENZ. 

